Suction lift means for industrial lift trucks



RE 91in? y 7, 1959 w. w. CUSHMAN 2,893,581

SUCTION LIFT MEANS FOR INDUSTRIAL LIFT TRUCKS Filed 001;. 51, 1957 INVENTOR 16 5 WaLiOn Wcuslzman BY m ATTORNEY United States Patent SUCTION LIFT MEANS FOR INDUSTRIAL LIFT TRUCKS Walton W. Cushman, Webb City, Mo.

Application October 31, 1957, Serial No. 693,790

3 Claims. (Cl. 214-651) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

,with the top surface of a package to be lifted and transported. Such equipment was restricted in its use to packages of given cubic contents and height due to the fact that the vacuum bell was supported by and carried beneath the conventional fork or forks of the truck which normally are just above floor level.

One of the important objects of the present invention is to provide lift means as aforesaid which is capable of lifting and transporting packages of extremely large size and of great height and weight.

Another object is to provide auxiliary means for creating a vacuum for use in emergencies due to failure of the engine of the industrial lift truck; a further object is to provide means having a greater contact area with the package to be lifted and transported whereby substantially the entire surface area of the top of the package is subjected to vacuum or suction; and a still further object is to provide for the lifting of cargo, etc., without the attending wastage of space heretofore occupied by the conventional pallet, or other device, normally used to get under the load.

The foregoing and other objects and advantages of the present invention will appear from the following description and appended claims.

In the accompanying drawing, forming a part of this application, and in which like reference numerals are employed to designate similar parts in the several views:

Figure 1 is a side elevational view, partly broken away, of a conventional fork lift truck, showing the application thereto of one embodiment of the present invention;

Figure 2 is a somewhat enlarged scale bottom plan view, partly in section, of the package-engaging or contacting means of the invention;

Figure 3 is a vertical longitudinal section, taken substantially along the line 33 of Figure 2, looking in the direction of the arrows;

Figure 4 is an enlarged scale detail in transverse vertical section, taken substantially along the line 4-4 of Figure 3 looking in the direction of the arrows; and

Figure 5 is an enlarged scale detail view, being a section along the line 55 of Figure 2, looking in the direction of the arrows.

Referring now particularly to the drawing, there is shown in Fig. 1 a more or less conventional industrial lift truck, of either the fork or platform type, with one embodiment of the present invention applied thereto.

2,893,581 Patented July 7, 1959 The numeral 10 designates the truck as a whole which has a pair of front wheels 11 and a pair of rear wheels 12, the latter being mounted on a pair of stub axles (not shown) and operated for steering purposes by a steering wheel 13 located adjacent the operators seat 14. Trucks of this type are usually provided with an upright frame or mast 15 upon which a load-supporting carriage 16 is slidably mounted.

These industrial trucks are in nearly universal use in conjunction with pallets or skids for transporting and storing goods at freight depots, warehouses, etc., and are generally provided with a pair of plain fork members adapted to enter the space between the upper and lower surfaces of the pallets.

In accordance with my invention, instead of providing a pair of conventionally mounted fork members, I employ horizontally and forwardly extending spaced members or arms 17, 17 which have depending portions or member 18, 18 at their inner ends, which latter are attached to portions of the supporting carriage 16 to be raised and/ or lowered with said carriage.

As shown, a preferably square steel plate 20 is attached at spaced points 21, to the under face of the horizontal spaced members 17, 17. The under face or surface of plate 20 carries a rubber hose, shown as a whole at 22, and attached to said plate in any desired manner, as by means of spaced bolt and nut assemblies 23, see particularly Fig. 5. The hose is also bonded to plate 20 throughout its entire length, as indicated at 24 in Fig. 5, and preferably follows the outline or configuration of plate 20, see Fig. 2. I

The space or area beneath plate 20, which is surrounded or framed by hose 22, is capable of having air exhausted therefrom to create a vacuum at that location. For this purpose, there is a connecting hose or conduit 25 which is forked adjacent its rear or inner end to provide branches 26 and 27. Branch 26 extends to and is connected with the intake manifold 9 of the truck engine. Branch 27 extends to and is connected with an electrically powered vacuum pump assembly 8. This pump assembly is of a conventional type and is provided for emergency use in the event of failure of the truck engine. -It is arranged to be actuated by a conventional pressure switch 7 which may be set to cut in at approximately 14" Hg.

Plate 20 has a centrally disposed hole or passage 20a and has affixed to the top face thereof, in airtight manner, a casting 28 having an air port or passage 29 in communication with hole 20a and hose or conduit 25. Casting 28 has an externally threaded upper reduced end portion or boss 30. An internally threaded coupling nut or collar 31 serves to attach the adjacent end of hose or conduit 25 to boss 30 of the casting, in conventional manner, to provide an airtight joint or connection.

The lift means of the present invention is adapted particularly, although not exclusively, for use in the handling of packages such as package I, Fig. 1, similar to my aforesaid Letters Patent No. 2,709,519. Packages in accordance with this patent have square or rectangular ends, each of which presents an area which is only slightly greater than the area defined by seal or hose 22 and steel plate 20. Thus, when the hose 22 and steel plate 20 are placed upon the top end of package P, see Fig. 1, and the air is exhausted in the area defined by hose 22, either as the result of the conduit 25, 26 connection with the intake manifold 9, or the conduit connection 25, 27 with the vacuum pump 8, a vacuum is created over virtually the entire top surface area of package P. As the result, the package P is actually lifted from the bottom by atmospheric pressure as the lifting means is actuated.

By reason of the arrangement and relatively high position of the fork-like members or arms 17 and the steel plate '20, it is possible to engage and handle packages, such as package P, which are of relatively great height. This would not be possible, however, if the arms were located so as to project forwardly from the lower ends of portions or members 18.

It is to be understood that suitable means is provided so that, in the event of engine failure, thus terminating the suction supply, or vacuum, from intake manifold 9, the immediate seating of the spring-pressed ball valve 32 in boss 30, see Fig. 4, prevents the loss of vacuum in the space or area surrounded by seal 22 between plate 20 and the top of package P, due to any feed-back of air or gases from the engine intake manifold. Simultaneously, any loss in vacuum in line 25 to a suction bel ow approximately 14 Hg, causes the closing of the pressure switch (not shown) thus starting the auxiliary electric vacuum pump 8 to maintain the necessary vacuum in said space or area.

A check valve (not shown) but similar to the valve 32, Fig. 4, is located in line 26 to prevent its losing vacuum through the engine intake manifold system.

To assure an uninterrupted suction supply to the space or area surrounded by the seal 22 and between plate 20 and the top of package P, a guard or protector, in the form of a wire screen 33 is attached to the under face of plate 20 surrounding the aligned hole 20a and passage 29 (Fig. 4).

Obviously, the invention is not limited to the embodiments herein shown and described, but may assume other forms.

I claim:

1. Package engaging and lifting means for mounting upon an industrial truck in which the truck includes an internal combustion engine, an upright frame and a load-supporting carriage slidably mounted on said upright frame, said means comprising arms projecting forwardly from said carriage and having depending portions afiixed to said carriage to move therewith, a generally square steel plate carried by and depending from said arms, a flexible continuous sealing member bonded to the underside of said plate following the generally square outline of the plate and disposed adjacent the four edges thereof whereby to provide a suction area of substantial size between said plate and the package, and a flexible conduit interconnecting the steel plate and the intake manifold of the internal combustion engine.

2. Package engaging and lifting means for mounting upon an industrial truck in which the truck includes an internal combustion engine, an upright frame and a loadsupporting carriage slidably mounted on said upright frame, said means comprising arms projecting forwardly from said carriage and having depending portions aflixed to said carriage to move therewith, a generally square steel plate carried by and depending from said arms, a flexible continuous sealing member bonded to the underside of said plate following the generally square outline of the plate and disposed adjacent the four edges thereof whereby to provide a suction area of substantial size between said plate and the package, and a protective wire screen attached to the under face of the steel plate within the area defined by the sealing member.

3. Package engaging and lifting means for mounting upon an industrial truck in which the truck includes an internal combustion engine, an upright frame and a load-supporting carriage slidably mounted on said upright frame, said means comprising arms projecting forwardly from said carriage and having depending portions afiixed to said carriage to move therewith, a steel plate carried by and depending from said arms, a flexible continuous sealing member bonded to the underside of said plate following generally the outline of the plate and disposed adjacent the periphery thereof whereby to provide a suction area of substantial size between said plate and the package, a flexible conduit interconnecting the steel plate and the intake manifold of the internal combustion engine, and a protective wire screen attached to the under face of the steel plate within the area defined by the sealing member.

References Cited in the file of this patent UNITED STATES PATENTS 2,169,739 Owen Aug. 15, 1939 2,347,491 Lente Apr. 25, 1944 2,622,750 Ehlers Dec. 23, 1952 2,687,226 Garrett Aug. 24, 1954 2,708,046 Oushman May 10, 1955 2,732,957 Horner Jan 31, 1956 2,815,240 Lytle Dec. 3, 1957 

